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Correspondence IL:trackIL und IS:track [message #3500] Fri, 07 March 2025 14:49 Go to next message
Stéphane Kaloustian is currently offline  Stéphane Kaloustian
Messages: 8
Registered: September 2024
Junior Member
Dear railML Interlocking community,

In an interlocking / MMI view at SBB there exists three types of track:

  • A centralized track Element (with tvdSection) => example: track 5
  • A track Element whithout tvdSection (non centralized track) => example: track 46
  • A virtual track Element (for train routing) => example: track 64
IL:trackIL - railML 3 Wiki states: "trackIL has a 1:1-relation to a track element in functional infrastructure" and then "refersTo (1..1)" which have 2 different meanings:

  • One IL:trackIL corresponds to exactly one IS:track, and one IS:track shall not correspond to more than one IL:trackIL (in which case the drawing below is wrong)
  • Problem: in this case IS:track must be interrupted at every Signal, where the tvdSection has its boundaries. For this, an element of type "border" must be placed, because a trackBegin / trackEnd can only be located at switches / bufferStops / borders / crossings
  • An IL:trackIL must have one reference to an IS:track (in which case the drawing below is conform)
Please consider the images in the attached PDF file.

Questions:

  • Must there be a corresponding and identical "IS:track" element for each "trackIL" element?
  • If yes, how to model a virtual track element for which no physical track exists?
  • If yes, how is trackIS interrupted at tvdSection-boundaries? => border@type="track"?
  • Does it make sense to interrupt the "IS:track" element, even though this is only necessary from the point of view of the interlocking / control system?
Looking forward to your inputs and discussion,
Stéphane Kaloustian and Silvan Gruber
SBB Swiss Railways

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Re: Correspondence IL:trackIL und IS:track [message #3512 is a reply to message #3500] Sun, 16 March 2025 07:48 Go to previous messageGo to next message
Jörg von Lingen is currently offline  Jörg von Lingen
Messages: 114
Registered: March 2016
Senior Member
Dear Stéphane,

thanks for the detailed description of the issue.

Here we have to improve the documentation for the use of these elements and
their relations.
1) The childs trackBegin / trackEnd of IS:track are not mandatory. Thus it is
conceivable to have an IS:track not beginning or ending at switches /
bufferStops / borders / crossings.
You might think of ending an IS:track at the station limits in order to allow
for macro and mesa view onto the infrastructure.
2) The relation between IS:track and trackIL is meant that one trackIL shall not
refer to more than one IS:track. However, one IS:track might have several
trackIL referring to. Thus, the phrase "1:1" is misleading.
3) The trackIL is seen in its functional / operational sense. Thus one trackIL
might not be congruent to one IS:track in its extent, i.e. one trackIL is a
subset of an IS:track.
For example some infrastructure managers split platform tracks for the
operational purpose of joining or splitting trains.
4) Virtual tracks as trackIL might have a reference to one IS:track but not
necessarily.
5) Not centralized Tracks without tvdSection are also possible, i.e. trackIL
refers to IS:track but does not have a child hasTvdSection.
6) A tvdSection might be related to several trackIL and vice versa.

Best regards,
Joerg v. Lingen - Interlocking Coordinator

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Re: Correspondence IL:trackIL und IS:track [message #3660 is a reply to message #3512] Mon, 23 June 2025 14:31 Go to previous message
christian.rahmig is currently offline  christian.rahmig
Messages: 529
Registered: January 2016
Senior Member
Dear Stephane,

for trackUS: trackBegin and trackEnd are optional from syntax, but they can become mandatory from use case. Therefore, always look inside the use case element specification table, too, in order to find out if trackBegin and trackEnd have to be provided.

Best regards
Christian

Christian Rahmig – Infrastructure scheme coordinator
railML.org (Registry of Associations: VR 5750)
Altplauen 19h; 01187 Dresden; Germany www.railML.org

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